Electro-stimulators for providing electrical stimulation to muscles are known. An example is an electro-stimulator in Patent Literature 1 that includes electrodes for outputting current, sensors for detecting information on motion of a knee joint, and a supporter to which the electrodes and the sensors are attached, to be worn around a lower limb. This electro-stimulator adjusts magnitude of current output from the electrodes according to results of detection by the sensors.
By the above-described electro-stimulator, abdominal muscles cannot be trained properly.